To create simple hover enlarge plugin, try this. (DEMO)
HTML
<div id="content">
<img src="http://www.freevectorgallery.com/wp-content/uploads/2011/10/Vintage-Microphone- 11395-large.jpg" style="width:50%;" />
</div>
js
$(function () {
$('#content img').hover(function () {
$(this).toggle(function () {
$(this).width('70%');
});
});
});